Answer:
3.24 x 10⁴
Step-by-step explanation:
There are only three sig figs in the starting integer, so to express that in Scientific Notation, you should have the same number of sig figs in the final answer.
Place a pointer at the end of the number 32,400, which should start behind the end of this number, which would be "32,400."
Move it to the left until you land on a number that IS NOT zero.
The number of spaces you've moved is the number of significant figures.
So once you get to the end, you'll notice you moved FOUR spaces, which explains why you are multiplying it by 10⁴.